EP0173869A1 - Flame-retardant thermoplastic polymer composition - Google Patents

Abstract

The polymer mixtures contain specific thermoplastic polycarbonates based on tetraalkylated diphenols, specific aromatic phosphate esters and optionally tetrafluoroethylene polymers in combination with styrene polymers and/or graft polymers.

Description

• a) thermoplastische, halogenfreie, schwefelfreie und phosphorfreie, aromatische Polycarbonate, die 50 Mol-% bis 100 Mol-%, vorzugsweise 75 Mol-% bis 100 Mol-%, insbesondere 90 Mol-% bis 100 Mol-%, und ganz besonders 100 Mol-%, bifunktionelle Struktureinheiten der Formeln (1) und/oder (2) enthalten,
  
  
  
  worin X eine Einfachbindung, ein C₁-C₅-Alkylen, ein C₂-C₅-Alkyliden, ein Cyclohexylen, Cyclohexyliden oder ein zweibindiqer Rest der Formel
  
  ist, und
  50 bis 0 Mol-%, vorzugsweise 25 Mol-% bis 0 Mol-%, insbesondere 10 _Mol-% bis 0 Mol-%, und ganz besonders 0 Mol-%, andere bifunktionelle Struktureinheiten der Formel (3) enthalten,
  
  
  worin -O-D-O- andere halogenfreie, schwefelfreie und phosphorfreie Diphenolat-Reste als die in den Struktureinheiten (1) und (2) sind, vorzugsweise nur aus C-, H- und O-Atomen aufgebaut sind und vorzugsweise 6 bis 30 C-Atome haben,
• b) halogenfreie Styrolpolymere mit mittleren Gewichtsmittelmolekulargewichten Mw zwischen 10 000 und 600 000 und/oder
• c) halogenfreie Pfropfpolymere von halogenfreien Monomeren auf halogenfreie Kautschuke, denen ein Kautschuk:Pfropfmonomeren-Gewichtsverhältnis von 93 %:7 % bis 5 %:95 %, vorzugsweise von 90 %: 10 % bis 70 %:30 % und von 50 %:50 % bis 10 %: 90 % zugrundeliegt
• d) halogenfreie und schwefelfreie Phosphatester der Formel (7)
  
  
  worin R1, R₂ und R₃ gleich oder verschieden und C₁-C₂₀-Kohlenwasserstoffreste sind, wobei mindestens zwei der Reste R₁, R₂ und R₃ substituierte oder unsubstituierte Arylreste sind, und gegebenenfalls
• e) Tetrafluorethylenpolymerisate enthalten, wobei die Komponente a) in Mengen von 25 bis 95 Gew.-%, vorzugsweise 35 bis 90 Gew.-%, insbesondere von 45 bis 90 Gew.-% und ganz besonders bevorzugt von 45 bis 70 Gew.-% und 80 bis 90 Gew.-%, vorliegt, die Komponente
• b) in Mengen von 2 bis 74 Gew.-%, vorzugsweise von 5 bis 65 Gew.-% und insbesondere von 9 bis 54 Gew.-% vorliegen kann,
  die Komponente c) in Mengen von 2 bis 74 Gew.-%, vorzugsweise von 5 bis 65 Gew.-% und insbesondere von 9 bis 54 Gew.-% vorliegen kann,
  die Komponente d) in Mengen von 1 bis 45 Gew.-%, vorzugsweise von 2,5 bis 30 Gew.-%, besonders bevorzugt von 4 bis 20 Gew.-% und insbesondere von 5 bis 15 Gew.-% vorliegt, und
  die Komponente e) in Mengen von 0 bis 5 Gew.-%, vorzugsweise von 0,02 bis 2 Gew.-%, besonders bevorzugt von 0,04 bis 1 Gew.-% und insbesondere von 0,05 bis 0,5 Gew.-% vorliegen kann,
  wobei die Summe der Komponenten b) + c) mindestens jeweils 4 Gew.-% und die Summe aller Komponenten jeweils 100 Gew.-% beträqt.
  Vorzugsweise beträgt der Anteil der Komponenten b) und/ oder c) höchstens 75 %, insbesondere höchstens 50 %.

The present invention relates to flame-retardant, thermoplastic polymer mixtures, characterized in that they

• a) thermoplastic, halogen-free, sulfur-free and phosphorus-free, aromatic polycarbonates, the 50 mol% to 100 mol%, preferably 75 mol% to 100 mol%, in particular 90 mol% to 100 mol%, and very particularly 100 Contain mol%, bifunctional structural units of the formulas (1) and / or (2),
  
  
  
  wherein X is a single bond, a C ₁ -C ₅ alkylene, a C ₂ -C ₅ alkylidene, a cyclohexylene, cyclohexylidene or a two-membered radical of the formula
  
  is and
  Preferably contain 50 to 0 mol% 25 mol% to 0 mol%, in particular 10 _M ol-% to 0 mol%, and especially 0 mol%, of other bifunctional structural units of the formula (3),
  
  
  wherein -ODO- are halogen-free, sulfur-free and phosphorus-free diphenolate residues than those in the structural units (1) and (2), are preferably made up only of C, H and O atoms and preferably have 6 to 30 C atoms ,
• b) halogen-free styrene polymers with average weight-average molecular weights Mw between 10,000 and 600,000 and / or
• c) halogen-free graft polymers of halogen-free monomers on halogen-free rubbers which have a rubber: graft monomer weight ratio of 93%: 7% to 5%: 95%, preferably from 90%: 10% to 70%: 30% and from 50%: 50 % to 10%: based on 90%
• d) halogen-free and sulfur-free phosphate esters of the formula (7)
  
  
  wherein R1, R ₂ and R _{3 are} identical or different and C ₁ -C ₂₀ hydrocarbon radicals, at least two of the radicals R ₁ , R ₂ and R _{3 being} substituted or unsubstituted aryl radicals, and optionally
• e) contain tetrafluoroethylene polymers, component a) in amounts of 25 to 95% by weight, preferably 35 to 90% by weight, in particular 45 to 90% by weight and very particularly preferably 45 to 70% by weight % and 80 to 90% by weight is present, the component
• b) can be present in amounts of from 2 to 74% by weight, preferably from 5 to 65% by weight and in particular from 9 to 54% by weight,
  component c) can be present in amounts of 2 to 74% by weight, preferably 5 to 65% by weight and in particular 9 to 54% by weight,
  component d) is present in amounts of 1 to 45% by weight, preferably 2.5 to 30% by weight, particularly preferably 4 to 20% by weight and in particular 5 to 15% by weight, and
  component e) in amounts of 0 to 5% by weight, preferably 0.02 to 2% by weight, particularly preferably 0.04 to 1% by weight and in particular 0.05 to 0.5% by weight .-% may be present
  the sum of components b) + c) being at least 4% by weight and the sum of all components being 100% by weight.
  The proportion of components b) and / or c) is preferably at most 75%, in particular at most 50%.

The preferred ranges of components a) to e) inclusive are understood individually, i.e. they are not automatically linked to the preferred areas of the respective other components.

Based on the total weight of the respective polymer mixtures according to the invention, these should each contain 3 to 30% by weight, preferably 5 to 25% by weight and in particular 7 to 20% by weight of rubber in the presence of component c).

According to DE-OS 2 228 072, thermoplastic polycarbonates are made flame-retardant with a mixture of hexabromobenzene and an antimony compound, which may additionally contain a phosphate ester as a synergist.

Suitable polycarbonates are also those from tetraalkylated diphenols. The sole addition of 10 parts by weight of triphenyl phosphate to bisphenol A polycarbonate has no anti-drip effect according to the UL-Subj. 94 (see page 20 of _DE - _OS 2 228 072). Instead of the polycarbonates, mixtures of polyphenyl ether resins and styrene resins can also be made flame-retardant, 11% by weight being required if only phosphate ester is used (see page 10 of DE-OS 22 28 072).

Foamable thermoplastic materials are known from DE-OS 24 34 085, with polycarbonates, polymers or mixtures thereof being mentioned as thermoplastics. Polymers made from butadiene, styrene and acrylonitrile or from styrene alone are also mentioned. The foamable plastics can contain phosphate esters as flame retardants, optionally in combination with halogen compounds. No polytetrafluoroethylene polymers are recommended as halogen compounds and neither are those suitable according to the present invention suitable as polycarbonates.

According to DE-OS 2 921 325, the addition of pentaerythritol diphosphates is described as a flame retardant for polycarbonates, halogen compounds also being able to be used, which, according to page 9 of DE-OS 29 21 325 from the cited US Pat. No. 33 92 136, can also be polyvinylidene fluorides ; the polycarbonates which are suitable according to the present invention are not described. ABS copolymers can be mixed into the polycarbonates.

Flame retardant mixtures of polycarbonates, ABS polymers and halogen compounds are known (see DE-OS 2 903 100 and DE-OS 2 918 883). According to DE-OS 2 903 100, the flame resistance is achieved by special organic sulfonates. Fluorinated polyolefins can be added as anti-drip agents. According to DE-OS 2 918 883, the flame resistance is achieved by alkali or alkaline earth metal salts of acids in combination with anti-dripping agents, the ABS polymeri sate only a maximum of 10 parts by weight, based on the total mixture.

DE-OS 29 18 882 discloses molding compositions made from polycarbonates, halogen compounds, alkali metal or alkaline earth metal salts and fluorinated polyolefins which, as an additional thermoplastic resin, contain polycarbonates from tetraalkylated diphenols in amounts of up to 10% by weight, based on the mixture as a whole.

According to DE-OS 29 29 229 (Le A 19 751), special phosphites are used for the thermal stabilization of polycarbonate-ABS mixtures. The molding compositions may also contain flame retardants.

According to DE-OS 3 002 985, mixtures of special polyester combinations with graft polymers and aromatic polycarbonates are described; these mixtures can also contain flame retardants. Phosphorus compounds and halogen compounds are mentioned as flame retardants. Anti-drip agents can also be added (page 12 of DE-OS).

As polycarbonates, those of alkylated diphenols are described only indirectly via the cited US Pat. No. 4,034,016; polytetrafluoroethylene polymers are not addressed as halogen compounds.

According to US Pat. No. 3,671,487, glass fiber-reinforced thermoplastic polyesters based on glycols and iso- or terephthalic acid are used with flame-retardant additives tives, such as phosphate esters, and polytetrafluoroethylene. Aromatic, thermoplastic polycarbonates are not covered by the application. This is also not obvious, since the polyesters mentioned, unlike the amorphous polycarbonates, are partially crystalline thermoplastics with completely different properties.

According to EP-OS 00 74 112, phosphate esters are added as plasticizers to polycarbonate / ABS mixtures. Diphenyl octyl phosphate is mentioned, for example, as the phosphate ester. The special polycarbonates according to component a) of the present invention are not listed. The addition of fluorinated polyolefins is not described.

According to EP-OS 0 103 230 (Le A 21 835), the mixtures of components a), b) and / or c) of the present invention are made flame-retardant with polyphosphates, these having an Mw (weight average) of 1600 to 150,000 can. In addition, polytetrafluoroethylene can also be used. However, the polyphosphates are structurally different from the phosphates of the formula (7).

According to US Pat. No. 4,355,126 and US Pat. No. 4,107,232, among other things, flame-retardant ABS polymers are known which contain polytetrafluoroethylene. Triphenyl phosphate is particularly preferred as the flame retardant. In contrast, it was not to be expected that the addition of the polycarbonates based on tetraalkylated diphenols would result in more flame-retardant molding compositions.

The polymer mixtures according to the invention have flame-retardant properties, determined in a known manner according to UL subject 94 or according to the 0 ₂ index according to ASTM-D-2863-A.

The present invention thus also relates to the use of the polymer mixtures according to the invention as flame retardants for the production of flame-retardant articles made of thermoplastic materials.

The polycarbonates according to component a) which can be used according to the invention can be branched in a known manner by the incorporation of halogen-free, sulfur-free and phosphorus-free branching agents.

Halogen-free polycarbonates in the sense of the present invention means that the polycarbonates are composed of halogen-free diphenols, halogen-free chain terminators and optionally halogen-free branching agents, the content of minor ppm amounts of saponifiable chlorine, resulting, for example, from the production of the polycarbonates with phosgene by the phase interface process is to be regarded as containing halogen in the sense of the invention. Such polycarbonates with ppm contents of saponifiable chlorine are halogen-free polycarbonates in the sense of the present invention. The same applies to sulfur-free or phosphorus-free polycarbonates; S- or P-containing impurities, resulting, for example, from working up the polycarbonate, would not count.

The preparation of the polycarbonates which can be used according to the invention is known and is described, for example, in German Offenlegungsschriften No. 2 211 957 and No. 2 615 038.

sind beispielsweise:

• Bis-(3,5-dimethyl-4-hydroxyphenyl), Bis-(3,5-dimethyl-4-hydroxyphenyl)-methan, 1,1-Bis-(3,5-dimethyl-4-hydroxyphenyl)-ethan, 2,2-Bis-(3,5-dimethyl-4-hydroxyphenyl)-propan, 1,1-Bis-(3,5-dimethyl-4-hydroxyphenyl)-2-methyl-propan, 2,2-Bis-(3,5-dimethyl-4-hydroxyphenyl)-butan, 2,4-Bis-(3,5-dimethyl-4-hydroxyphenyl)-2-methylbutan, 1,1-Bis-(3,5-dimethyl-4-hydroxyphenyl)-cyclohexan und α, α' -Bis-(3,5-dimethyl-4-hydroxyphenyl)-p-diisopropyl- benzol.

Diphenols of the formula (4) on which the structural unit (1) is based

are for example:

• Bis (3,5-dimethyl-4-hydroxyphenyl), bis (3,5-dimethyl-4-hydroxyphenyl) methane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) ethane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) -2-methyl propane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) butane, 2,4-bis (3,5-dimethyl-4-hydroxyphenyl) -2-methylbutane, 1,1-bis (3,5-dimethyl-4 -hydroxyphenyl) -cyclohexane and α, α 'bis (3,5-dimethyl-4-hydroxyphenyl) -p-diisopropyl-benzene.

Preferred diphenols of the formula (4) are:

2,2-bis- (3,5-dimethyl-4-hydroxyphenyl) methane and 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, the latter especially as Rohbis ^p henol as it can be used in accordance with the processes of DOS 2 928 464 and DOS 2 928 443 from pure 2,6-dimethylphenol and from technical 2,6-dimethylphenols contaminated, in particular with cresols, can be used. Such crude bisphenols, however, must contain at least 80% by weight, preferably at least 90% by weight, of 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane.

The particularly preferred diphenol of formula (4) is bis (3,5-dimethyl-4-hydroxyphenyl) methane.

ist ebenfalls ein bevorzugtes Diphenol.The diphenol (5) on which the structural unit (2) is based

is also a preferred diphenol.

Diphenols of the formula (6) on which the structural unit (3) is based

• Resorcin, Dihydroxydiphenyle, Bis-(hydroxyphenyl)-alkane, Bis-(hydroxy-phenyl)-cycloalkane, Bis-(hydroxyphenyl)-ether, Bis-(hydroxyphenyl)-ketone und α,α'-Bis-(hydroxyphenyl)-diisopropylbenzole.

are for example:

• Resorcinol, dihydroxydiphenyls, bis (hydroxyphenyl) alkanes, bis (hydroxyphenyl) cycloalkanes, bis (hydroxyphenyl) ethers, bis (hydroxyphenyl) ketones and α, α'-bis (hydroxyphenyl) diisopropylbenzenes .

Diphenols of this type are described, for example, in the monograph "Hermenn Schnell, Chemistry and Physics of Polycarbonates", New York, Interscience Publishers, 1964, Polymer Reviews, Vol 9.

Preferred diphenols (6) are, for example

Bis (4-hydroxyphenyl), 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxyphenyl) propane, bis (hydroxyphenyl) methane (also mixtures of isomers), 2, 2-bis (3-methyl-4-hydroxyphenyl) propane and α, α'-bis (4-hydroxyphenyl) p-diisopropylbenzene.

Particularly preferred diphenols (6) are, for example, 2,2-bis (4-hydroxyphenyl) propane and bis (4-hydroxyphenyl) methane.

The polycarbonates which can be used according to the invention generally have molecular weights M (weight average, for example determined by the light scattering method) from 10,000 to 200,000, preferably from 20,000 to 80,000, particularly preferably from 25,000 to 60,000 and very particularly preferably from 30,000 to 45,000.

According to the invention which can be used according to Phosphatester ^Comp: component d) are those of formula (7)

wherein R ₁ , R ₂ and R _{3 are} identical or different and are C ₁ -C ₂₀ hydrocarbon radicals, at least two of the radicals R ₁ , R ₂ and R _{3 being} substituted or unsubstituted aryl radicals.

Preferred hydrocarbon radicals are those with 2 to 16 carbon atoms, in particular those with 6 to 10 carbon atoms. Preferred aryl radicals are also those with 6 to 10 carbon atoms.

Suitable hydrocarbon radicals are alkyl, cycloalkyl and aralkyl radicals. Unsubstituted aryl radicals are, for example, phenyl and naphthyl. Substituted aryl radicals are alkaryl, cycloalkaryl, aryl-substituted alkaryl and aryl-substituted aryl radicals.

Examples of alkyl radicals are methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, neopentyl, 3,5,5-trimethylhexyl, 3-methylhexyl, 2-ethylhexyl and 2.5, 5-trimethylhexyl.

An example of a cycloalkyl radical is cyclohexyl.

Examples of aralkyl radicals are benzyl and phenethyl.

Examples of alkaryl radicals are o-, p- and m-tolyl, 2,6- and 2,4-dimethylphenyl, trimethylphenyls, o-, p- and m-isopropylphenyls, nonylphenyl, p-tert-butylphenyl, 2,4-diisopropylphenyl and Triisopropylphenyl.

An example of a cycloalkaryl radical is o-cyclohexylphenyl. Examples of aryl-substituted alkaryl radicals are p-benzylphenyl and p-phenethylphenyl.

An example of an aryl-substituted aryl is diphenyl.

Preferred radicals are phenyl, o-, m-, and p-tolyl, 2,6-dimethylphenyl, 2,4-diisopropylphenyl and triisopropylphenyl.

Preferred phosphate esters of formula (7) are those where the R ₁ , R ₂ and R ₃ radicals are aryl radicals or alkaryl radicals.

• Bis-(phenyl)-methylphosphat, Bis-(phenyl)-ethylphosphat, Bis-(phenyl)-butylphosphat, Bis-(4-methylphenyl)-2-ethylhexylphosphat, Bis-(phenyl)-2-ethylhexylphosphat, Bis-(phenyl)-octylphosphat, Bis-(phenyl)-isodecylphosphat, Tris-(phenyl)-phosphat, Tris-(2-methylphenyl)-phosphat, Tris-(3-methylphenyl)-phosphat, Tris-(4-methylphenyl)-phosphat, Tris-(2,6-dimethylphenyl)-phosphat, Tris-(isopropylphenyl)-phosphat, Tris-(nonylphenyl)-phosphat, Bis-(phenyl)-2-methylphenylphosphat, Bis-(phenyl)-4-methylphenylphosphat, Bis-(phenyl)-isopropylphenylphosphat, Bis-(phenyl)-2,6-dimethylphenylphosphat, Bis-(2-methylphenyl)-phenylphosphat, Bis-(4-methylphenyl)-phenyl- phosphat, Bis-(isopropylphenyl)-phenylphosphat, Bis-(2,6-dimethylphenyl)-phenylphosphat, Bis-(2,6-dimethylphenyl)-4-tertiär-butylphenylphosphat, Bis-(2,6-dimethylphenyl)4-methylphenylphosphat, Bis-(2,6-dimethylphenyl)-3-methylphenylphosphat, Bis-(2,6-dimethylphenyl)-4-iso- propylphenylphosphat und Bis-(2,6-dimethylphenyl)-2-isopropylphenylphosphat.

Examples of the aromatic phosphates of the formula (7) which can be used according to the invention are:

• Bis (phenyl) methyl phosphate, bis (phenyl) ethyl phosphate, bis (phenyl) butyl phosphate, bis (4-methylphenyl) -2-ethylhexyl phosphate, bis (phenyl) -2-ethylhexyl phosphate, bis (phenyl) ) octyl phosphate, bis (phenyl) isodecyl phosphate, tris (phenyl) phosphate, tris (2-methylphenyl) phosphate, Tris (3-methylphenyl) phosphate, tris (4-methylphenyl) phosphate, tris (2,6-dimethylphenyl) phosphate, tris (isopropylphenyl) phosphate, tris (nonylphenyl) phosphate, bis- (phenyl) -2-methylphenyl phosphate, bis (phenyl) -4-methylphenyl phosphate, bis (phenyl) isopropylphenyl phosphate, bis (phenyl) -2,6-dimethylphenyl phosphate, bis (2-methylphenyl) phenyl phosphate, bis (4-methylphenyl) phenyl phosphate, bis (isopropylphenyl) phenyl phosphate, bis (2,6-dimethylphenyl) phenyl phosphate, bis (2,6-dimethylphenyl) -4-tertiary-butylphenyl phosphate, bis (2nd , 6-dimethylphenyl) 4-methylphenyl phosphate, bis- (2,6-dimethylphenyl) -3-methylphenyl phosphate, bis- (2,6-dimethylphenyl) -4-isopropylphenyl phosphate and bis- (2,6-dimethylphenyl) -2 -isopropylphenyl phosphate.

• Tris-(phenyl)-phosphat, Tris-(methylphenyl)-phosphat, Tris-(2,6-dimethylphenyl)-phosphat, Bis-(phenyl)-methyl- phenylphosphat, Bis-(methylphenyl)-phenylphosphat, Bis-(2,6-dimethylphenyl)-phenylphosphat und Bis-(2,6-dimethylphenyl)-methylphenylphosphat.

Preferred phosphates of the formula (7) are:

• Tris (phenyl) phosphate, tris (methylphenyl) phosphate, tris (2,6-dimethylphenyl) phosphate, bis (phenyl) methyl phenyl phosphate, bis (methylphenyl) phenyl phosphate, bis (2 , 6-dimethylphenyl) phenyl phosphate and bis (2,6-dimethylphenyl) methylphenyl phosphate.

• Tris-(phenyl)-phosphat, Tris-(methylphenyl)-phosphat und Bis-(phenyl)-methylphenylphosphat.

Particularly preferred phosphates of the formula (7) are:

• Tris (phenyl) phosphate, tris (methylphenyl) phosphate and bis (phenyl) methylphenyl phosphate.

Tetrafluoroethylene polymers according to component c) which can be used according to the invention are polymers with fluorine contents of 65 to 76% by weight, preferably 70 to 76% by weight. Examples are polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymers or tetrafluoroethylene copolymers with small amounts of fluorine-free, copolymerizable, ethylenically unsaturated monomers. Polytetrafluoroethylene is preferably used. The polymers are known. They can be used in finely divided form, usually as a powder. They can be prepared by known processes, for example by polymerizing tetrafluoroethylene in an aqueous medium with a free radical-forming catalyst, for example sodium, potassium or ammonium peroxydisulfate at pressures of 7 to 71 kg / cm ² and at temperatures of 0 to 200 ° C, preferably at temperatures of 20 to 100 ° C. (For more details, see, for example, U.S. Patent 2,393,967.)

The polytetrafluoroethylenes suitable according to the invention should preferably have weight average molecular weights Mw between 10 ⁵ and 10.

Halogen-free styrene polymers according to component b) are understood to mean homopolymers and copolymers which contain at least 50% by weight of at least one monomer from the group of Styren and its halogen-free derivatives copolymerized. This group includes, for example, styrene, cC-methylstyrene, p-methylstyrene, 3,4-dimethylstyrene, o- and p-divinylbenzene and p-methyl-α-methylstyrene. Styrene, cC-methyl- and p-methylstyrene are preferred, styrene and p-methylstyrene are particularly preferred, and styrene itself is very particularly preferred.

In addition to styrene and its derivatives, the styrene polymers of this invention can contain up to 50% by weight of at least one halogen-free monomer from the group of acrylic and methacrylic compounds and the group of unsaturated dicarboxylic anhydrides in copolymerized form. The first group includes e.g. Acrylic and methacrylic acid, acrylonitrile, methacrylonitrile, methyl acrylate, ethyl acrylate, n- and iso-propyl acrylate, n- and iso-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n- and iso-propyl methacrylate, n- and iso-butyl methacrylate, cyclohexyl methacrylate and n-and iso-butyl methacrylate, . From this group, acrylonitrile and methyl methacrylate are preferred. The preferred monomer of the second group is maleic anhydride.

Preferred halogen-free styrene polymers are in particular polystyrene, styrene / acrylonitrile copolymers with 1.5 to 15% by weight of acrylonitrile content, styrene / methyl methacrylate copolymers, styrene / maleic anhydride copolymers with up to 20% by weight of maleic anhydride and styrene / acrylonitrile / maleic anhydride Copolymers with 1.5 to 15% by weight of acrylonitrile and up to 20% by weight of maleic anhydride. Prefers of these are polystyrene and the styrene-acrylonitrile copolymers mentioned, very particularly preferably the latter. The styrene polymers to be used according to the invention should have average weight-average molecular weights Mw (measured in DM _F at c = 5 g / 1 and 20 ° C.) between 10,000 and 600,000 and can be carried out in a known manner by bulk, suspension or emulsion polymerization in the presence of catalysts getting produced.

(Literature: Beilstein's Handbook of Organic Chemistry, 4th edition, 3rd supplement, volume 5, pages 1163 to 1169, Springer-Verlag, 1964; H. Ohlinger, polystyrene, 1st part, manufacturing process and properties of the products, Springer Verlag 1955).

Halogen-free graft polymers according to component c) are understood to mean halogen-free rubbers grafted with at least one halogen-free monomer. Halogen-free monomers which can be used are those mentioned above, which are listed for the preparation of the styrene polymers to be used according to the invention. The monomers listed there as preferred and particularly preferred are likewise preferably or particularly preferably used in the grafting of the rubbers to give graft polymers.

Any halogen-free rubbers can be used as the graft base for the production of the halogen-free graft polymers to be used according to the invention. Butadiene rubbers with up to are preferred 50% by weight of copolymerized halogen-free comonomers, preferably styrene or acrylonitrile, in particular polybutadiene. Halogen-free acrylic ester rubbers and halogen-free polyolefin rubbers such as ethylene-propylene-diene terpolymers are also preferred. Particularly preferred halogen-free rubbers are polybutadiene and halogen-free acrylic ester rubbers. Rubbers of this type are described, for example, in German Offenlegungsschriften No. 23 29 585 and No. 31 18 861. The halogen-free graft polymers to be used according to the invention should have a rubber: graft monomer weight ratio of 93%: 7% to 5%: 95%, preferably from 90%: 10% to 70%: 30% and from 50%: 50% to 10% : 90%. Such graft polymers can be obtained by known processes, for example by the process of emulsion polymerization or suspension polymerization.

Graft polymers to be preferably used according to the invention are those which consist of halogen-free rubber and grafted styrene, methyl methacrylate, styrene / acrylonitrile mixture, styrene / methyl methacrylate mixture or styrene / maleic anhydride mixture. Graft polymers consisting of rubber and a grafted styrene-acrylonitrile mixture with an acrylonitrile content of 1.5 to 15% by weight, based on the grafted styrene-acrylonitrile mixture, are particularly preferred.

As already mentioned, the graft polymers can be prepared by known processes, as is the case with is set out, for example, in the two above-mentioned laid-open publications.

The graft polymer is preferably obtained by radical polymerization of the graft monomer (s) in the presence of the rubber which is the graft base. The graft polymerization of more than one monomer onto the rubber is to be carried out in such a way that the resin component of the graft polymers has the desired monomer ratio after the polymerization. "Graft pad" is understood to mean the entire polymerized part of the monomers used for the graft polymerization, irrespective of the proportion of the monomers which has been chemically linked to the rubber. The graft polymer component (C) to be used according to the invention can therefore also consist of an intimate mixture of grafted polymer and homo- or copolymer.

Styrene polymers and graft polymers in the sense of this invention are also understood to mean mixtures of styrene polymers and mixtures of graft polymers.

The mixtures according to the invention are prepared in a known manner.

The flame-retardant thermoplastic mixtures according to the invention show good properties. The compatibility of the aromatic poly usable according to the invention Carbonates, styrene polymers and aromatic phosphates are so good that completely transparent polymer mixtures can be obtained in some cases. When polytetrafluoroethylene is used according to the invention, these transparent mixtures can become translucent. When graft polymers are used according to the invention, they can become translucent to opaque. Even with a larger aromatic phosphate content, the flame-retardant thermoplastic mixtures according to the invention do not become sticky and show a glossy, high-quality surface. Furthermore, when using pure starting components, they are colorless to whitish-opaque. Of particular interest is the good flame resistance of the polymer mixtures according to the invention, which can be seen in part in extremely short burning times and extremely low tendency to drip.

They also have relatively high heat resistance and good mechanical properties. Their flow seam strength is excellent. They are very resistant to hydrolysis. In thermoplastic processing, they have a high flowability even at a relatively low processing temperature. They are very stable in processing, even at high processing temperatures. Furthermore, their light and weather stability is high.

The high flame resistance of the thermoplastic polymer mixtures according to the invention is particularly surprising even with small proportions of aromatic phosphate. Furthermore, it is particularly surprising, as by using a little polytetrafluoroethylene in the inventive Polymer mixtures the burning times after flame treatment can be drastically reduced. It is also particularly surprising how the aromatic polycarbonates containing bis- (3,5-dimethyl-4-hydroxyphenyl) methane condensed in. The flame resistance in the thermoplastic polymer mixtures according to the invention can be increased considerably, as well as by using styrene. Acrylonitrile copolymers and styrene-acrylonitrile-grafted rubbers in which the content of acrylonitrile in the polymerized styrene-acrylonitrile mixture is 1.5-15% by weight.

The flame-retardant thermoplastic polymer mixtures according to the invention with O ₂ indices above 24%, but in particular with 0 ₂ indices above 26%, are preferred, but are particularly preferred. it prefers with 0 ₂ indices over 28% and in particular over 30%. However, mixtures are very particularly preferred if they are in accordance with UL Subj. 94 achieve the classifications V II, VI and V 0, the degree of preference being in the order of classification mentioned.

The polymer mixtures according to the invention can also be used for the thermoplastic polycarbonates and / or for the styrene polymers and / or for the graft polymers, such as fillers such as minerals or carbon black, reinforcing materials such as glass fibers or carbon fibers, stabilizers such as UV, oxidation and thermal stabilizers, mold release agents, dyes or Contain pigments or other common additives.

The polymer mixtures according to the invention can be used wherever the use of flame-retardant plastics, in particular flame-retardant polycarbonate / polymer mixtures, is required, for example in the appliance sector, in the electrical and electronics sector, in the installation and heating sector and in the transport sector.

Examples of the use of the flame-retardant polymer mixtures according to the invention are coffee machines, electric cookers, grills, irons, washing machines, film devices, slide projectors, cabling, telephone systems, telex systems, cable television systems, electric motors, air conditioning systems, computing systems, lighting systems, electrical installations in the residential and industrial sectors, radio sets, television sets , Turntables, VCRs, automobiles and planes.

Some specific examples of the use of the polymer mixtures according to the invention are ashtrays in automobiles, food trays in airplanes, instrument carriers in automobiles, lamp holders, carriers of electrical and electronic components in a wide variety of devices, and covers for fuse elements and power switches in electrical systems.

example 1

Flame resistance of mixtures of various polycarbonates, graft polymers, triphenyl phosphate and polytetrafluoroethylene

Zu Tabelle 1

• MPC = Polycarbonat aus 2,2-Bis-(3,5-dimethyl-4-hydroxy-phenyl)-propan (TMBPA), rel = 1,297 (5 g/1 in CH₂C1₂ bei 25°C).
• FPC = Copolycarbonat aus Bis-(3,5-dimethyl-4-hydroxyphenyl)-methan (TMBPF) und TMBPA 75/25 Molteile, rel = 1,295 (5 g/l in CH₂C1₂ bei 25°C).
• ACR = Pfropfpolymerisat mit Kern-Mantel-Struktur der folgenden Zusammensetzung, ausgedrückt in Gewichtsverhältnissen der es bildenden Monomeren: n-Butylacrylat/Butandiol-1,3- diacrylat/ Diallylmaleat/Methylmethacrylat = 79,2/ 0,4/0,4/20,0.
• ABS = Pfropfpolymer aus 50 Gewichtsteilen Styrol/ Acrylnitril-Copolymer (72/28 Gewichtsteile) als Pfropfauflage und 50 Gewichtsteile Polybutadienkautschuk der mittleren Teilchengröße 0,4 µm als Pfropfgrundlage.
• ABS^* = Pfropfpolymer aus 50 Gewichtsteilen Styrol/ Acrylnitril-Copolymer (90/10 Gewichtsteile) als Pfropfauflage und 50 Gew.-Teile Polybutadienkautschuk der mittleren Teilchengröße 0,4 µm alsPfropfgrundlage.
• TP_P = Triphenylphosphat
• PTFF = Polytetrafluorethylen pulverförmig (Hoechst _AG, Hostaflon TF 2026).

The mixtures listed in Tab. 1 were produced in a twin-screw extruder at approx. 290 ° C via the melt. The mixtures were then processed in extrusion injection molding to test specimens which were subjected to the flame retardancy tests listed in Table 1. As can be seen from Table 1, the tests yielded the following results. With a combination of triphenyl phosphate and polytetrafluoroethylene, mixtures of the polycarbonates and graft polymers according to the invention can be considerably improved in their flame retardancy (see Example 1a-1h). When using graft polymers with a styrene / acrylonitrile graft base with a low acrylonitrile content (here styrene / acrylonitrile ratio 90/10 parts by weight), particularly short burning times are achieved (comparison example 1d with 1f). When polycarbonate containing predominantly bis- (3,5-dimethyl-4-hydroxyphenyl) methane is used, mixtures with 10% graft polymer show good flame retardancy even without the addition (see example 1 g), but the flame retardancy is increased by the addition of triphenyl phosphate and PTFE increased considerably (see example 1h).

To table 1

• MPC = polycarbonate from 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane (TMBPA), rel = 1.297 (5 g / 1 in CH ₂ C1 ₂ at 25 ° C).
• FPC = copolycarbonate of bis (3,5-dimethyl-4-hydroxyphenyl) methane (TMBPF) and TMBPA 75/25 molar parts, rel = 1.295 (5 g / l in CH ₂ C1 ₂ at 25 ° C).
• ACR = graft polymer with a core-shell structure of the following composition, expressed in weight ratios of the monomers forming it: n-butyl acrylate / butanediol-1,3-diacrylate / diallyl maleate / methyl methacrylate = 79.2 / 0.4 / 0.4 / 20 , 0.
• ABS = graft polymer made from 50 parts by weight of styrene / acrylonitrile copolymer (72/28 parts by weight) as a graft and 50 parts by weight of polybutadiene rubber with an average particle size of 0.4 µm as a graft base.
• ABS ^* = graft polymer made from 50 parts by weight of styrene / acrylonitrile copolymer (90/10 parts by weight) as the graft and 50 parts by weight of polybutadiene rubber with an average particle size of 0.4 µm as the graft base.
• TP _P = triphenyl phosphate
• PTFF = powdered polytetrafluoroethylene (Hoechst _A G, Hostaflon TF 2026).

Information about flame resistance UL Subject 94, _P rüf- body strength 1.6 mm (see Table 1..): Nd = not passed; V II, VI, V 0 = flame retardancy classes; Figures on the top row = number of test specimens with burning times ≤ 10 sec / ≤ 30 sec / ≤ 30 sec burning droplets /> 30 sec;

Figures below row: Sum of the afterburning times of the test specimens stored 2 days at 23 ° C / Sum of the afterburning times of the test specimens stored 7 days at 70 ° C / longest single afterburning time. The figures in addition to the flame retardancy class provide additional information for assessing flame retardancy.

Example 2

Flame resistance of mixtures of TMBPF / TMBPA copolycarbonate 75/25 molar parts, SAN or ABS as well as triphenyl phosphate and possibly polytetrafluoroethylene.

The mixtures listed in Table 2 were prepared and processed into test specimens, as described in Example 1. As can be seen in Table 2, the tests yielded the following results. The addition of 5% by weight Triphenylphosphate to the mixtures of TMBPF / TMBPA copolycarbonate 75/25 Morteile and SAN or ABS increases their flame retardancy considerably (cf. 1st example 2 a and 2 b, 2 e and 2 f). The addition of 0.2 part by weight of polytetrafluoroethylene further reduces the burning times (s, UL Subject 94, Ex. 2 b and 2 c and Ex. 2 f and 2 ^g ). Increasing the amount of triphenylphosphate from 5 to 10% by weight while the amount of polytetrafluoroethylene remains the same further shortens the burning times (see UL Subject 94, Ex. 2 c and 2 d and Ex. 2 g and 2 h).

To Tab. 2

FPC, ABS ^* , TPP, PTFE Explanation as in Ex. 1 nb, V II, VI and VO; Explanation as in Ex. 1 Numbers under "UL subject 94" = Explanation as in Ex. 1. SAN = styrene-acrylonitrile copolymer (90/10).

Claims (6)

1. Thermoplastic polymer mixtures, characterized in that they a) thermoplastic, halogen-free, sulfur-free and phosphorus-free, aromatic polycarbonates which contain 50 mol% to 100 mol%, bifunctional structural units of the formula (1) and / or (2),

wherein X is a single bond, a C ₁ -C ₅ alkylene,. a C ₂ -C ₅ alkylidene, a cyclohexylene, cyclohexylidene or a divalent radical of the formula

is and 50 to 0 mol%, preferably 25 mol% to 0 mol%, in particular 10 mol% to 0 mol%, and very particularly 0 mol%, contain other bifunctional structural units of the formula (3),

wherein -0-DO- are other halogen-free, sulfur-free and phosphorus-free diphenolate residues than those in the structural units (1) and (2), are preferably composed only of C, H and O atoms and are preferably 6 to 30 C- Atoms have halogen-free styrene polymers with average weight-average molecular weights Mw between 10,000 and 600,000 and / or halogen-free graft polymers of halogen-free monomers on halogen-free rubbers, which have a rubber: graft monomer weight ratio of 93%: 7% to 5%: 95%, preferably of 90 %: 10% to 70%: 30% and 50%: 50% to 10%: 90% underlies halogen-free and sulfur-free _P hosphatester of formula (7),

wherein R ₁ , R ₂ and R _{3 are the} same or different and are C ₁ -C ₂₀ hydrocarbon radicals, at least two of the radicals R ₁₁ R ₂ and R _{3 being} substituted or unsubstituted aryl radicals, and optionally e) contain tetrafluoroethylene polymers, component a) being present in amounts of 25 to 95% by weight, component b) being in amounts of 2 to 74% by weight, component c) being in amounts of 2 to 74 % By weight, component d) may be present in amounts of 1 to 45% by weight, and component e) may be present in amounts of 0 to 5% by weight, the sum of components b) + c) is at least 4% by weight and the sum of all components is 100% by weight. 2. Polymer mixtures according to claim 1, characterized in that component a) is present in amounts of 35 to 90% by weight. 3. Polymer mixtures according to claim 1, characterized in that component d) is present in amounts of 2.5 to 30% by weight. 4. Polymer mixtures according to claim 1, characterized in that component e) is present in amounts of 0.02 to 2% by weight. 5. Polymer mixtures according to claim 1, characterized in that component b) and / or component c) are each present in amounts of 5 to 65% by weight. 6. Use of the polymer mixtures of claims 1 to 5 as a flame retardant for the production of flame retardant objects made of thermoplastic materials.